Apparatus for furnace-slag disposal



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C. G. HAWLEY APPARATUS FOR EURNAGE SLAG DsPOSAL Filed Jan. l5 1921 Mx h Patented pr. l?, 1923.

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CHARLES GILBERT HAWLEY, 0F CHICAGO, ILLINOIS.

combustion and which may be referred to for an understanding of the chief objects and features of my generic invention. Therefore I shall set forth herein only the special objects, features and structures which are individual to this particular case.

When pulverized fuel is burned in suspension according to modern methods, thel fuel ash is deposited upon the walls and Hoor of the combustion chamber in the form of slag. While it has been proposed to continuously discharge this slag from the combustion chamber vthe actual performance thereof has not been accomplished, with the result that wherever modern pulverized fuel burning chambers or boxes are in use Ait is the practice to periodically shut them down, allow them to cool ofi', and then to'break up the accumulated slag and remove it. There are many attendant difficulties and losses.

l have. succeeded in overcoming this difficulty by very simple means, to-wit, I provide a hole at the bottom or low oint of the combustion chamber through w ich the slag may drain away and in addition I provide means for keeping the margins of the drain hole so highly heated as to prevent the freezing of the slag therein; and thus the slag-drain hole is kept open at'all times.

My invention is not limited to use with pulverized fuel, but is adapted to all other furnaces wherein the fused ash or slag is deposited upon a bottom floor or hearth from which it must be discharged or drained if the furnace is to be kept in continuous operation. v

Thel invention will be readily understood on reference to the accompanying drawings; in which Fig. 1 is a vertical longitudinal scc-tion of a steam boiler setting which includes a pulverized-fuel combustion-chamber Application filed Januaryllf, 1321. Serial No. 437,615.

APPARATUS FonrUaNAoE-snao Drsrosar..

and myslag hole heating invention; Fig.2

is a vertical cross-section on the line 2 2 of Fig.'1; Fig. 3 is a transverse vertical sec.

tion of two steam boilers arranged to be fired by. a single inverted semi-suspension combustlon furnace of a type such as I have disclosed in my application, Serial No. 437,-

614, together with the invention specifically treated of in this application; and Fig. 4 is an enlarged horizontal section on the line 4 4 of Fig. 3.

Fig. 1 illustrates the ordinary pulverized fuel burning furnace arranged for heating a boiler, A. The boiler is supported on the Hoor, 2. The combustion chamber, 3, is a downward continuation of the fire space, A', directly beneath the boiler. Inmost cases the. combustion chamber, 3, is of a depth which equals, and ,often exceeds, the height of the boiler. Its walls, 3', are composed of refractory brick. tain air admission openings, 4. The fuel falls into the chamber, 3, from one or more fuel nozzles, 5. The'general play of the flame developed within the chamber, 3, is indicated by the dotted lines, 5', from which 1t wlll be seen that virtually the whole box is filled with dame.

Before proceeding to the description of the slag-hole feature of this invention, l first wish to direct attention to a matter of novelty which I introduce in pulverized coal burning furnaces. In one or several walls lof the chamber, 3,'I provide firebrick panels, 6, containing many relatively. small a1r feeding openings, 4. The panel, as a whole, is vprotected from down-flowing slag One or more walls con-v to prevent the closing of the holes, 4'. The i protecting means may be an 'overhanging ledge, 3. On the outer side, the whole panel, '6, is enclosed by a shield, 8, open at the end 7, on the inner wall ofthe chamber,-

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or side, as shown at 9, for the admission. of-

the air required to support the combustion of the fuel in the chamber, 3. The opening or duct, 9, contains a regulating damper, 10'. The advantage of the described con-- in the shape of a ho per, 11, which is lined with firebrick. At t e low point this hopper is provided with the slag drain-hole, 12, leading into the slag pit, 13. Preferably there is an overhanging ledge, 14, at the lower end of the hole, 12. Extremely high temperatures are obtained in the combustion chamber, 3, and all of the ash Which is deposited on the Hopper bottom is readily maintained in a molten state provided it is not permitted to collect thereon in any considerable quantity or depth.

Such accumulation of 'slag is prevented by my invention, which proceeds to the burning of a'fire (indicated by dotted lines, 15), against or beneath the overhanging ledge, 14, of the slag hole, allowing the hot gases of combustion to rise into the combustion chamber, 3,.through the slag hole. A small quantity of fuel, consumed in a burner such as 16, is entire-ly` adequate to keep the mar-` gins of the slag hole at temperatures which ensure the free draining of the molten slag from the bottom of the combustion chamber. Thus it becomes possible to continue the operation 0f the furnace indefinitely, for this invention makes it unnecessary to shut down the furnace at any time to remove ash or slag accumulations therefrom.

By preference, I limit the inrush of air to the slag pit, lest an excess of cold air be present to cool the margins of the slag hole. It is desirable that the slag pit shall be normally sealed against the entrance of cold air in response to the chimney draft existing in the chamber, 3.

In Fig. 3 I have disclosed a desirable use of the inverted semi-suspension combustion furnace described and claimed in my Serial No. 437,614, the said furnace being positioned overa lateral tire passage, B', in such manner as to heat'the adjacent steam boilers, C. C'. Obviously the same arrangement is suited to asingle boiler. The pomt of interest in the case is that with a furnace of the type B, the flame is delivered downwardly from the furnace outlet7 18, and from said outlet, 18, the slag of combustion falls upon the lioor or hearth, 19, of the fire passage, I3. To prevent the accumulation and freezing of the slag 0n this floor, I provide it with a slag drain-hole, 20, through which the slag may drain into a slag-pit, 21. Surrounding the walls of the hole, 20, is an annular chamber, 22,- in which either a gas liquid, or solid,'fuel fire maybe maintained (as by the means appearing in Fig. 4) tofkeep the walls of the slag hole hot, as required by this present invention.

It will be found that this invention is adapted for extensive application throughout the field of fuel combustion.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. The improvements herein described,

comprising a combustion chamber wherein fuel ash is slagged, and having a slag drain hole in its bottom, in combination with a slag pit, and combustion means for heating the margins of said slag hole, substan tially as and for the purpose specified.

2. The improvements herein described. comprising a combustion chamber wherein fuel ash is slagged, said chamber having a slag drain hole in its bottom, in combination With a slag pit, and means for maintaining a separate fire in the top of said slagpit for heating. the margins of said slag hole` substantially as and for the purpose specified.

3. The improvements herein described comprising a combustion chamber wherein fuel ash is slagged,l and having a slag drain hole in combination with'parate heating means for heating the margins of the slag hole, substantially as and for the purpose specified.

In testimony whereof, I have hereunto set my hand this 11th day of January, 1921.

CHARLES GILBERT HAWLEY. 

